A STUDY OF THE EFFECT OF MOBILITY RATIOS ON PATTERN DISPLACEMENT BEHAVIOR AND STREAMLINES TO INFER PERMEABILITY FIELDS PERMEABILITY MEDIA SUPRI TR 115 By Yuandong Wang Anthony R. Kovscek William E. Brigham December 1998 Work Performed Under Contract No. DE-FG22-96BC14994 Prepared for U.S. Department of Energy Assistant Secretary for Fossil Energy Thomas Reid, Project Manager National Petroleum Technology Office P.O. Box 3628
44
Embed
A STUDY OF THE EFFECT OF MOBILITY RATIOS ON ...1. A study of the effect of mobility ratios on pattern displacement behavior It is well known, for unit mobility ratio, that the areal
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
A STUDY OF THE EFFECT OF MOBILITY RATIOS
ON PATTERN DISPLACEMENT BEHAVIOR AND
STREAMLINES TO INFER PERMEABILITY
FIELDS PERMEABILITY MEDIA
SUPRI TR 115
By
Yuandong Wang
Anthony R. Kovscek
William E. Brigham
December 1998
Work Performed Under Contract No. DE-FG22-96BC14994
Prepared forU.S. Department of Energy
Assistant Secretary for Fossil Energy
Thomas Reid, Project ManagerNational Petroleum Technology Office
P.O. Box 3628
ii
TABLE OF CONTENTS
List of Figures iii
Acknowledgments iv
Abstract v
Chapter 1 Effect of Mobility Ratio on Pattern Behavior of
A Homogeneous Porous Medium ..................................................... 1
aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a aa a
aaa
aa
aa
a
aaa
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a aa a a a a aa a
aaaaaaa
aaaaaa
aa
aaa
aaa
a
aaa
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a aaa a a a a a a aa a a a a a a a a a aaa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a aaa a a a a aa a a a aaaaaaaaaaaaaaaaa
aa
aaa
aaa
aaa
a
aaa
a
aaa
a
a
a
aa
a
a
a
a
aaa
a
a
a
a
a
aa
a
a
a
a
a
aa
aa a a a aa a a a a aa a a a a a aaa a a a a aaa a a a a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a aa a a a a a a a a aaa a a a a aa a
a a aa aaaaaaaaaaaaaaaaaaaaaa
aaa
aa
a
aa
a
aaa
a
aaa
a
aaa
a
a
aaa
a
a
aaa
a
a
a
aa
a
a
a
aa
aa a a aaa a aaa
a a aaaa a a aa a a a a aa a a a a a aa a a a a a a a aa a a a a a a a a a a aa a a a a a a a a a a aa a a a a a a a aa a a a a aaa
a a aaaaaaaaaaaaaaaaaaaaaaaaaaa
aa
aaa
aaa
aaa
aaa
a
aaa
a
aa
a
a
aaa
a
aaa
a
a
aaa
a
aa
aa a aaaa aa
a a aa a a aaaa a aa a a a aa a a a a aa
a a a a aaa a a a a a aaa a a a a a a a aaa a a a a a a a a aa a a a a a a aa aa a a aaa
a a aaaaaaaaaa
aaa
aaaaaaaaaaaaa
aa
aa
aaa
aa
a
aa
a
aa
a
aa
a
aaa
aaa
a
aaa
a
aa
a
a
aa
a
aa
aa aaaaaaaaaaaaaaaaaaa aa a a aaa
a a aa a a a aaaa a a a aa
a a a a a aaa a a a a a a aaa a a a a a a aaa a a a a a aa a a a a aa a a a aaaa aaaaaaaaaaaaaa
aa
aaaaaaaa
aa
aa
aaa
aa
aaa
aaa
aaa
aaa
aaa
aaa
a
aa
a
aaa
aa
aaaaaaaaaaaaaaaaa
aaaaa aaaaaaa a aa
a a aaaa a aaa
a a a aaaa a a a aaa a a a a a a aa a a a a a a aa a a a a a aa a a a a aa a a aaa
aaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaa
aa
aaa
aa
aaa
aaa
aa
a
aa
a
aa
a
aa
a
aa
aa
aaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
a a aa a a a aa a a a a aaa a a a aaa a a a a a aa a a a a a aaa a a a a aaa
a a a aa a a a aaaa aaaaaaaaaaaaaaaaaaa
aaaaaaaa
aa
aa
aa
aaa
aa
aaaaa
aaa
aa
aaa
aaa
aa
aa
aaaa
aaaaa
aaaaaaaa
aaaaaaaaaaaaaaaaaaaaaaa a aaa
a a aa aa a a aa
a a a a aa a a a a a aa a a a a a aaaa a a a aa a a a aaa
a a aa a aaaaa aaaaaaaaaaa
aaaaa
aa
aa
aaaaaa
aa
aa
aa
aaaaa
aa
aaa
aa
aaa
aa
aaaa
aaaaaa
aaaaaaaaaaaaaaaaaaaaaaa
aaa
aaaaaaaaaaa a aaa
a a aa a a a aaaa a a aaa
a a a a aaaa a a a aaa
a a a aaaa a a aa a a a aa
a a aaaaaaaaa
aaa
aaaaaaaa
aaaaaaaaaaaaaaaaaa
aa
aa
aaaaa
aa
aaaaaa
aaaaaaaaaa
aaaaaaa
aaaaaaaaaaaaaaaaaa
aaaaaaaaaaaa aa a a aaa
a a a aaa a a a aa
a a a a aaaa a a a aa a
a a a aaaa a a aa a a aaa
a aaaaaaaaaaaaa
aaa
aaaaa
aaaaaaa
aa
aa
aa
aa
aa
aa
aa
aa
aaaaaaaaaa
aaa
aa
aaaaaaaaaaaaa
aaaaaaa
aaaaaaaaaa
aaaaaaaaaaaaaaaaa
a a aa a a a aa a a a a aa a a a a aaaa a a a aa a
a a a aaaa a a aa a a aaa
a a aaaaaaaaaaaaaaaaaa
aaaaa
aaaaaaa
aa
aa
aa
aa
aa
aa
aa
aa
aa
aaa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
aaa
a
aa
aaaaaa aa a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a
aa
a
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
aa
a
a
a
aaa
a
aaa
aaa
aa
aaaa
aaaaaaaaa a aa a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a
a
aa
a
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
aaa
a
a
a
aa
a
a
aaa
a
aaa
aaa
aaa
aa
aaaaaa
aaaaa
aaaaaaa
a a aa a a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a aa a a a a a a a a a aa a a a a a a a aa a a a a a aa
aa
a
a
a
aa
a
a
a
aaa
a
a
aaa
a
a
aaa
a
aaa
a
aaa
a
aa
a
aa
aaa
aa
aaaaaaaaaa
aaaaaaaaaa aa a
a a aa aa a a a aa a a a a a a a a aaa a a a a a a a a a a a a aaa a a a a a a a a a a a aa a a a a a a a aaa a a a a a aaa
a a a a aa a a a a aa a a a aa
aa
a
aaa
a
a
aaa
a
aaa
a
aaa
a
aaa
a
aa
a
aaa
aaa
aaa
aa
aaaaaaaaaaaa
aaaaa
aaaaaaaa aa a a a aa a a a a aaa a a a a a a a aa a a a a a a a a a a aa a a a a a a a a a aaa a a a a a a aa a a a a a aa a a a a aa a a a aaa
a a aaaa a aa a
a aa
aa
a
aa
a
a
aa
a
aaa
a
aaa
aaa
a
aa
a
aa
a
aa
aaa
aaaaa
aa
aa
aa
aa
aaaaaaa
aaaaaaaaaaa aa a a a aa a a a a aaa a a a a a a aa a a a a a a a a aa a a a a a a a a aa a a a a a a aa a a a a aaa
a a a aa a a a aa a a aaaa a aa a
aaaaaaa a aa
aa
aaa
a
aa
a
aa
a
aaa
aaa
aaa
aaa
aa
aaa
aaaaa
aa
aa
aa
aa
aa
aaaaa
aaaaaaaaaaaaa aaa
a a aaaa a a a aa
a a a a a aaa a a a a a a aaa a a a a a a aaa a a a a a aaa a a a aa a a a aa a
a a aa a a aa aaaaaaaaaaaaaaaaaaaaa
aa
aa
a
aa
a
aa
a
aa
a
aa
aaa
aaa
aa
aaaaa
aa
aaaaaaaaaaaa
aaaaa
aaaaaaaaaa aaa a aa a a a aa
a a a aaaa a a a a aa a a a a a a aa a a a a a a aa a a a a a aa a a a a aa a a a aa a a aaa
aaaaaaaaaaaaaaaaaaaaa
aaa
aaa
aa
aa
aa
aaa
aaa
aa
aaa
aa
aaa
aa
aaaaa
aa
aa
aa
aa
aa
aaaaaaa
aaaaaaaa
aaaaaaaa a aa
a a aaaa a a aaa
a a a a aaa a a a a a aa a a a a a aaaa a a a aa a a a aaa
a a aaaa aaa
aaaaaaaaaaaaaa
aaaaaaaaa
aaa
aaaaaaa
aaaa
aa
aaa
aa
aaa
aa
aa
aaaaa
aa
aa
aa
aa
aa
aaaaaaa
aaaaa
aaaaaaaaaaaaa a aaa
a a aaaa a a aa a a a a aaa
a a a a a aa a a a a a aaa a a a aa a a a aaa
a a aa a aaaaaaaaaaaaaa
aaaaaaaaa
aaaaaaaa
aaaaaaaa
a
aaaaaa
aa
aaaaaaa
aa
aa
aaaaaaaaaaaa
aaaaaaa
aaaaa
aaa
aaaaaaaaaaa a aa a a aaa
a a a aaaa a a a aa
a a a a a aaa a a a aaa
a a a aaaa a aaa
a a aa aaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaa
aaaaa
aaaaaaaa
aaaaaaaaaaaa
aa
aa
aa
aa
aa
aaaaaaaaa
aaaaaaaaaa
aaa
aaa
aaaaa aa
a a aa a a a aa a a a aaaa a a a aa a a a a a aa
a a a a aa aa a a aa a a a aa a a aaa
aaaaaaaaaaaaaaaaaaaaaa
aaaaa
aaaaaaa
aaaaaaaaa
aaa
aaa
aa
aa
aa
aa
aa
aa
aa
aaaaaaaaa
aaaaa
aaaaa
aaaaaaaaaaaaaa aa
a a aa a a a aa a a a aaaa a a a aa a a a a a aa
a a a a aa aa a a aa a a a aa a a aa a
aaaaaaaaaa
aaa
aaa
aaaaa
aaaaa
aaaaaaaaaaaaaaa
aa
aa
aaa
15
line-drive than in a five-spot pattern. Therefore, when the shortest streamtube breaks
through, a larger portion of the other streamtubes have been swept in a staggered-line-
drive than in a five-spot pattern. When d / a increases, the streamtube length ratio
(longest to shortest) decreases. When breakthrough happens in the shortest streamtube, a
greater portion is swept in the longest streamtube resulting in higher sweep efficiency at
breakthrough.
1.5.3 Five-Spot Pattern, Very Favorable Mobility Ratio
For a favorable mobility ratio ( M < 1), the displacement is stable. For equal
volumetric flow rate streamtubes, Eq. 10 holds. Here, we consider the case of very
favorable mobility ratio, i.e., the displacing fluid viscosity is much higher than that of the
displaced fluid. When the front moves a portion of the way down the streamtube, the
pressure drop is mainly in the displacing phase. That is to say, after a short injection time
(compared to breakthrough), the pressure drop in the displaced phase is negligible.
Therefore, Eq. 10 can be simplified to the following form
1
w0
lti∫ dl ≅ C (12)
In this extreme case, the displacing phase does not feel the producer until it is very close
to it because the pressure drop between the front and the well plays a negligible role in
the displacement. Initially, flow around the injector is radial, because the pattern appears
to be infinite at short times. For example, examine Fig. 6b for tD = 0.583. However, after
the front reaches a corner of the pattern, the no-flow boundary condition along pattern
borders alters the radial flow pattern. Pressure isobars must intersect the no-flow
boundaries at 90o. This constrains the streamlines in the region adjacent to a boundary to
be parallel to it. Because the fluids are incompressible, streamlines cannot terminate. The
flow field in the region near the front transitions from radial to quasi-radial. From the
figure, we also see that streamtubes ahead of the front are narrower along the boundary
than those in the center, which makes the front in the boundary streamtubes move faster
16
Fig 6 Five Spot Pattern, Very Favorable Mobility Ratio(1/M=20)
(a) Saturation Distribution
(b) Streamline Distribution
tD = 0.583
tD = 0.796
tD = 0.837
tD = 0.878
tD = 0.918
tD = 0.938
tD = 0.969
tD = 0.998
tD = 0.583
aa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a aaa a a a a a a a a a a aa
aaaa
aa
aa
aa
a
aa
a
a
aa
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a aa a a a a a a aa a a a a a a aa a a a a a a aaa a a a a a aaa a a a a a aaa a a a a a aa a a a a a aaa
aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a aaa
aaaaa
aa
a
aaa
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a
aaa
aaaaaaaa
aaa
a
aa
a
a
a
aaa
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
aa
aa a a a aaaa a a a aa a a a a a aaa a a a a a a aaa a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a aa
aaa
aa
aa
aa
a
aa
a
aa
a
a
aa
a
a
a
aaa
a
a
a
a
a
aa
a
a
a
a
a
a
a
aaa
a
a
a
a
a
aaa
a
a
a
aa
aa a a aaa a aaa
a a aaaa a a aa a a a a aaa
a a a a a aa a a a a a a a a aa a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a aaaaaaaaa
aa
a
aa
a
aaa
a
aa
a
a
a
aa
a
a
a
a
aaa
a
a
a
a
aaa
a
a
a
aaa
a
a
a
aa
a
a
aa
aa a aaaa aaaaaaa a aa
a a aa aa a aa a a a aaa
a a a a aa a a a a a a aa a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a aaaaaa
aa
aaa
aaa
aaa
a
aaa
a
a
aa
a
a
a
aaa
a
a
a
aa
a
a
a
aaa
a
a
aa
a
a
aa
a
aa
aaaaaaaaaaa
aaaaa aaaaaaaaaa
a a aaa a aaa
a a a aaaa a a a aa a a a a a a a a aa a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aa a a a a a a a a
aaa
aa
aaa
aaa
aaa
a
aa
a
a
aaa
a
a
aa
a
a
aaa
a
a
aaa
a
aaa
a
aaa
aaa
aa
aaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaa aa
a a aaaa a aaa
a a a aaaa a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a aaa a a a
aaa
aaa
aa
a
aa
a
aaa
a
aaa
a
aaa
a
aaa
a
a
aa
a
aaa
a
aa
a
aa
a
aa
aa
aaaa
aaaaa
aaaaaaaa
aaaaaaaaaaaaaaa
aaaaa aaa
a a aa a a a aaaa a a a aa a a a a a a a aaa a a a a a a a a a a a aaa a a a a a a a a a a a a a a aaa a a a a a a a aa
aaaa
aa
a
aa
a
aaa
a
aa
a
a
aa
a
aaa
a
aaa
a
aa
a
aa
a
aa
aaa
aaaa
aaaaaa
aaaaaaa
aaaaa
aaaaa
aaaaaaaaaaaaa aaaaaa a aaa
a a aaaa a a aaa
a a a a a aa a a a a a a a a a aa a a a a a a a a a a a a a a aa a a a a a a a a a a a a aa a a aaa
aaa
aa
a
aaa
aaa
a
aaa
a
aa
a
aaa
aaa
aaa
aaa
aa
aaaaaa
aaa
aaaaaaaaa
aa
aaaaaaa
aaaaa
aaaaa
aaaaaaaaaaaaaa aa
a a aaaa a aaa
a a a a aa a a a a a a a aa a a a a a a a a a a a aaa a a a a a a a a a a a a a aaa a a a a a a a aaa
a
aa
a
aa
a
aaa
aaa
a
aa
a
aaa
aaa
aaaaa
aaaaaaa
aaa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
aaa
a
a
aaa
a
aa
aaaaaaaaaa aa a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a
aa
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
aaa
a
a
a
a
aaa
a
a
a
aa
a
a
aaa
a
aa
a
aa
aaa
aa
aa
aaaaa
aaaaaa a a a aa a a a a a aa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
aaaaa a a aa a a a a a a a
a
aa
a
a
a
aaa
a
a
a
aa
a
a
a
aaa
a
a
aaa
a
a
aa
a
aaa
a
aa
a
aa
aaa
aaaaaaaaaa
aaaaa
aaaaaaa
a a aa a a a a aa a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a aaaaaaaaaa a
a a aa a a a aa
aa
a
aaa
a
a
aaa
a
aaa
a
aaa
a
aaa
a
aa
a
aaa
aaa
aa
aaa
aa
aaaaaaaa
aaaaaaaaaaaaaa a a aa a a a aaa
a a a a a aaa a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a aaaaa
aaaaaaaaaaa a aaa
a aa
aa
a
aa
a
aaa
a
aa
a
aaa
a
aa
a
aaa
aaa
aa
a
aa
aaaaa
aa
aa
aaaa
aaaaaaa
aaaaaaa aaaa aa a a a aa
a a a a aaa a a a a a a a a aa a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaaa
aa
aaaaaa
aaaaa
aaa
aaaa aa
aa
aaa
aaa
aaa
aaa
aaa
aaa
aaa
aa
aaa
aa
aaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaa a a aaa
a a a aaaa a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a
aaa
aa
aaa
aa
aa
aaaaaaa
aaa
aaa
aa
aa
aa
aaa
aaa
aa
a
aa
aaa
aa
aaa
aa
aa
aaaaaaaaaaaaaa
aaaaa
aaaaaaaaaaaaa a aa a
a a aaaa a a a aa a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a
aaa
aa
aaa
aaaaaaaaaaaaaa
aaaaaaa
aaaa
aa
aaa
aa
aaa
aa
aa
aaaaa
aa
aa
aa
aa
aaaaaaaaa
aaaaaaaa
aaaaaaaa aaa
a a aa a a a a aa a a a a a a aa a a a a a a a a a a aaa a a a a a a a a a a a a a a a aaa a a a a a a a a a aa
aa
a
aa
aaa
aaa
aa
aaaaaaaaaaaa
aaaaa
a
aaaaaa
aa
aa
aaaaaaaaa
aa
aa
aa
aaaaaaaaa
aaaaa
aaaaaaaaaaaaaaaa
a aaaa a a aa a a a a a aa a a a a a a a aaa a a a a a a a a a a a a a aa a a a a a a a a a a a a a aaa a a a a
aaa
aaa
aaa
aaa
aaa
aa
aaaaaaa
aaaaaaaaaa
aaa
aaaaaaaaaaaaaaaaaa
aa
aa
aaaaaaaaaaaaaaaaaaaaaaa aaa a aa a a a aa
a a a a aa a a a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a aaa a a a a a a a a a a aaaa
aaa
aaa
a
aa
a
aa
a
aa
a
aa
aaa
aa
aa
aa
aa
aa
aaa
tD = 0.90
aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aaaaaa
aaa
a
aa
aa a a a a a a a aa a a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a
aaaaaa
aa
aaa
aa
a
aaa
a
a
aaa
a
a
a
a
a
a
aa
a
aa a a a aa aa a a aaa
a a a a aaa a a a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaaaa
aa
aaa
aa
aaa
a
aaa
a
a
aaa
a
a
a
a
aaa
a
a
a
a
a
a
a
a
aa
a
aa a a aaa a aaa
a a aa aa a aaa
a a a aaaa a a a aaa a a a a a a a aa a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a aa
aaaa
aa
aaa
aaa
a
aa
a
a
aaa
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
a
a
aa
aa a aaaaaaaaaaaaaa a a aa
a a aaaa a aaa
a a a a aaa a a a a aaa a a a a a a a a aaa a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aa a a a a a
aaa
aa
aaa
aaa
a
aa
a
a
aaa
a
a
aaa
a
a
a
a
aa
a
a
a
a
aaa
a
a
a
aa
aaaaaaaaa aaaaaaaaaaaaaaaaa a aa a
a a aa a a a aaaa a a a aa a a a a a a aaa a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a aa
aaaa
aa
a
aa
a
aaa
a
aaa
a
a
aa
a
a
a
aaa
a
a
a
aa
a
a
a
aa
a
a
aa
aaaa
aaa
aaaaaaaaaaaaaaaaaaaaaaaaaa a aaa
a a aaaa a a aa a
a a a a aaa a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a aaa
aaa
aa
a
aaa
a
aa
a
a
aaa
a
a
aaa
a
a
aaa
a
a
aa
a
aaa
a
aa
aaaaaaaaa
aaaaa
aaaaaaaaaaaaaaaaaaaaaaa aa
a a aaaa a aaa
a a a a aaa a a a a a aa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a aa
aa
aa
a
aaa
a
aa
a
a
aa
a
a
aaa
a
aaa
a
a
aa
a
aaa
a
aa
aa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaa
aa aa
a a aaaa a a aa a a a a a aa a a a a a a a a aaa a a a a a a a a a a a a a aa a a a a a a a a a a a a a a aaa a a a a a
aa
a
aa
a
aaa
a
aa
a
a
aa
a
a
aaa
a
aaa
a
aa
a
aa
aaa
aa
aaa
aaaaaaaaaaa
aa
aaaaaaa
aaaaa
aaaaaaaaaaaaaaaaaaa a aaa
a a aaaa a a aaa
a a a a a a aa a a a a a a a a a a aaa a a a a a a a a a a a a a a a aa a a a a a a a a a a a aaaa
a
aa
a
aaa
a
aa
a
a
aa
a
aaa
a
aa
a
aaa
aa
aaaa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
aaa
a
a
a
aaa
a
aaa
aa
aaaa
aaaaaa a a aa a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
aa
aa
a
a
a
a
a
a
aaa
a
a
a
a
a
aaa
a
a
a
a
aaa
a
a
a
aa
a
a
aaa
a
aa
a
aa
aaa
aa
aaaa
aaaaa
aaa
aaaa
a a a aa a a a a a a aaa a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaaaa
a aa
aa
a
a
a
aa
a
a
a
aaa
a
a
a
aa
a
a
a
aa
a
a
aa
a
a
aa
a
aaa
aaa
aa
aaa
aa
aa
aaaaaaa
aaaa aaaaaa
a a aaaa a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aa
aa
aaaaaa aa
aa
a
aaa
a
a
aa
a
a
aaa
a
aaa
a
aa
a
aaa
a
aa
a
aa
aaa
aaaaa
aa
aa
aa
aaaaaaaaaa
aaaaaaa a a aa a
a a a aa a a a a a a a aaa a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aaaaa
aa
aaaaaaaa
aa
a
aa
a
aaa
a
aa
a
aaa
aaa
a
aa
a
aa
aaa
aaa
aa
aaaaa
aa
aa
aaaaaaa
aaaaaaaaaa aaa a aa a a a aaa
a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a aaa
aaa
aaaaa
aaaaaaaaaa
aa
aaa
aaa
aaa
aaa
aaa
aaa
aa
aaa
aa
aaa
aa
aa
aaaaaa
aa
aaaaaaaaaa
aaa
aaaaaaa a a a aa a a a a aa a a a a a a a aaa a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a aaa a a a
aa
a
aa
aaa
aaaaa
aaaaaaa
aa
aa
aa
aaa
aaa
aa
aaa
aaaaa
aaaaa
aa
aa
aaaaaaaa
aa
aaaaa
aaaaa
aaa
aaaaa aa
a a aaaa a a aa
a a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a aa
aa
a
aa
a
aa
a
aa
aaa
aa
aa
aaaaa
a
aaaa
aa
aaa
aa
aaaaa
aa
aaaaaaaaaaaaaaaaaaaa
aaaaa
aaaaaaaaaaaaaa aaa
a a aaaa a a aaa a a a a a a a aa a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a aa a a a a a a a
aaa
a
aa
a
aa
a
aaa
aa
aaa
aa
aa
aa
aaa
aaaaaa
aa
aa
aaaaaaaaaaaaaaaaaaaaaa
aaaaaaaaaa
aaaa aaaaaaaaa a a aaa
a a a aaaa a a a a aa a a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a aa a a
aa
a
aaa
a
aa
a
aaa
aaa
aaa
aa
aaaaaaaa
aaa
aa
aaaaaaaaaaaaaa
aa
aa
aaaaaaa
aaaaa
aaaaaaaaaaaa
aaaa a a aa a a a aa a a a a aaa a a a a a a aaa a a a a a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a aa
aa
a
aa
a
aaa
a
aa
a
aaa
a
aa
a
aa
aaa
aa
aa
aa
tD = 0.92
aa a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa
aaaaaa
aaa
a
aa
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a a aa a a a a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aaaa
aa
a
aa
a
a
aaa
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a aaa a a a aa
a a a a aa aa a a a aaa a a a a a a a aaa a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a
aa
aa
aaa
aaa
a
aaa
a
a
a
a
aa
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
aa
aa a aaaa a aa a a aaa
a a aaaa a a aa a a a a aaa
a a a a a aa a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a aa aaa
aaa
aaa
a
aaa
a
a
aaa
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
aa
a
a
a
aa
aa a aaaaaaaaaaa aa
a a aa a a aaaa a aa a
a a a aaa a a a aaa a a a a a a aaa a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a aa
aa
aaa
a
aaa
a
aaa
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
a
a
a
aa
a
a
a
a
aaa
a
aa
aaaaaaaaaaaaaaaaaaaaaaaaaa aa a
a aaaa a aaa
a a a aaaa a a a a aa a a a a a a a a aaa a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaa a a a a a
aaa
a
aa
a
a
aa
a
a
a
aa
a
a
a
a
aaa
a
a
a
a
aaa
a
a
a
a
aaa
a
a
aa
a
aa
aaaa
aaaaaaaaaaaaaaaaaaaaaa aaaaaaa aaa
a a aa a a a aa a a a a aaa a a a a a a aa a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a aa a
aaa
a
aaa
a
aaa
a
a
a
aa
a
a
a
a
aaa
a
a
a
aaa
a
a
aaa
a
aaa
aa
aaaaaaaaaaaaaa
aaaaa
aaaaaaaaaaaaaaaaa aaa a aa a a aaa
a a a aa aa a a a aaa a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a aa a a a a a a aa
aaa
a
aaa
a
a
aa
a
a
a
aaa
a
a
a
aa
a
a
a
aaa
a
aaa
a
aa
aa
aaaaaaaa
aaaaaaa
aaaaa
aaaaa
aaaaaaaaaaaaa aaaaaa a a aa a a a aa a a a a aa a a a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a aaa a a a a a a a a a a aaa a a
a
aa
a
a
aaa
a
a
aa
a
a
a
aaa
a
a
aaa
a
aaa
a
aaa
aaaa
aaa
aa
aaaaaaaaaaa
aaaaaaaaa
aaaaa
aaaaaaaaaaaaaaaaa aa a a aaa
a a a aa a a a a a aa a a a a a a a a aaa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a aaa a a a a a a aa
a
aa
a
a
aa
a
a
aaa
a
a
aaa
a
a
aa
a
aaa
a
aa
aaaa
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
aa
a
a
a
aa
a
aaa
aa
aa
aaaaaaaaa a aa
a a a a a aa a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a aaaaaa a
a
aa
a
a
a
a
a
aaa
a
a
a
a
a
aa
a
a
a
a
aaa
a
a
a
aa
a
a
aaa
a
aa
a
aaa
aa
aaaaaaaaaaaaaaa
aaaa a a aa a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
a
aaaa
aaa aa
aa
a
a
aaa
a
a
a
aa
a
a
a
aa
a
a
aaa
a
a
aa
a
aaa
a
aa
a
aa
a
aa
aaaaa
aa
aaaaaaa
aaaaaaa aa
a a aaaa a a aa a a a a a a a aa a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aaaaaaaaaa
aa
aa
a
aaa
a
aaa
a
aaa
a
aaa
a
aaa
aaa
a
aa
a
aa
aaa
aaaaa
aa
aa
aa
aa
aaaaa
aaaaaaa aaa a aa a a a aa a a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a
aaa
aaa
aa
aaaa
aaaa
aa
aaa
a
aa
a
aaa
a
aa
a
aaa
aaa
aaa
aa
aaa
aaaaa
aa
aa
aa
aa
aaaaaaa
aaaaaaa aaaaaa
a a aaaa a a aaa a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a
a
aaa
aaa
aaaaa
aaaaaa
aa
aa
a
aaa
aaa
aa
a
aa
a
aa
aaa
aa
aaa
aa
aaaaaaaaaaaaaa
aaaaaaaaaaaaaaa aa
a a aa aa a a aa
a a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a aaaa
a
aa
a
aaa
aaa
aaaaaaaaa
aa
aa
aaa
aa
aaa
aaa
aa
aaaaa
aa
aaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaaaa aaa
a a aaaa a a a aa a a a a a a a aa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aa a a a a a a a a aa
aa
a
aaa
a
aaa
aaa
aaa
aa
aaaaa
aaaa
aa
aaaaa
aa
aaaaa
aa
aa
aaaaaaaaaa
aa
aaaaaaaaaa
aaaaaaaaaaa aa a a aaa
a a a aa a a a a a aaa a a a a a a a a a aa a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a aa a a a aa
aa
a
a
aa
a
a
aa
a
aaa
a
aa
aaa
aa
aaa
aaaaaaaa
aa
aa
aa
aaaaaaaaaaaa
aa
aaaaaaa
aaaaa
aaaaaaaaaaaaa a a aa a a a aa a a a a aaa a a a a a a aaa a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a aaa a a a a a a a a aaa
a
aa
a
a
aa
a
a
aaa
a
aaa
a
aa
a
aa
aaa
aaa
aaa
aa
aa
aa
aa
aa
aa
aa
aa
aaaaaaa
aaaaaaa
aaaaaaaaaaaaaaaaa aa a a a aa
a a a aaaa a a a a aa a a a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a aa a a a a a
a
aaa
a
a
aa
a
a
aaa
a
aaa
a
a
aa
a
aaa
aaaaaa
tD = 0.94
aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a
aaa
aa
aa
a
aaa
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a a a a aaa a a a a a a aaa a a a a a a a a a aa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a aaa
aa
aaa
a
aaa
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
aa a a aaaa a a aaa
a a a aaaa a a a aaa a a a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a a a aa
aa
a
aa
a
aaa
a
a
a
aa
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
aa
aa a aaaa a aa
a a aa aa a aa a a a aaa
a a a aaaa a a a a aa a a a a a a a a aa a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a aa
aaa
aaa
a
a
aaa
a
a
a
a
aa
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
aa
aa aaaaaaaa aa
aaaaaaaa
a a aa a a aaaa a a aa a a a a aa a a a a a a aaa a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a aa a a a a a
a
aaa
a
aaa
a
a
aaa
a
a
a
a
a
aaa
a
a
a
a
a
a
aaa
a
a
a
a
a
a
aa
a
a
a
aa
aaaaaaaaaaaaaaaaa
aaaaa aa
aa aa a a aa a a a aa
a a a aaaa a a a aa a a a a a a a a aa a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a aaa a
a
aaa
a
a
aa
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
a
a
aaa
a
a
a
a
aa
a
a
aa
aaaa
aaaaaaaaaaa
aaa
aaa
aaaaaaaaaaaa aa
a a aa aa a aa a a a a aa a
a a a a a aa a a a a a a a a a aaa a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a aa a a a a a a a aa
a
aaa
a
a
aaa
a
a
a
aaa
a
a
a
a
aaa
a
a
a
a
aaa
a
a
aaa
a
aa
aaaaaaaaaaa
aaaaaaaa
aaaaaaaaaaaaaaaaaaaa aa a
a a aaa a a aa a a a a a aa a a a a a a a aa a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a aaa a a a a a a a a a aa a a a a
a
a
aaa
a
a
a
aa
a
a
a
aaa
a
a
a
a
aa
a
a
a
aaa
a
a
aa
a
aa
aaaaaaaa
aaaaaaa
aaaaaaa
aaaaaaaa
aaa
aaaaaaaaaaa a aa a a a aa a a a aaa
a a a a a aaa a a a a a a a a aaa a a a a a a a a a a a a a a aaa a a a a a a a a a a a a aa a a a a a a a aaa
a
a
aaa
a
a
aaa
a
a
a
aa
a
a
a
aaa
a
a
aaa
a
aaa
aa
aaa
aa
aaaaaaaaaaaaa
aaaaaaa
aaaaa
aaaaaaaa
aaaaaaaaaa a
a aaaa a a aa
a a a a aaa a a a a a a aaa a a a a a a a a a a a aaa a a a a a a a a a a a a a a aaa a a a a a a a a aaa a a a aa
a
a
aa
a
a
a
aa
a
a
a
aa
a
a
a
aa
a
a
aaa
a
aa
aa
aa
a
a
a
a
a
a
a
a
a
a
a
a
aaa
a
a
a
a
a
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
aa
a
a
aa
aaa
aa
aa
aaaaa
aaaa
a a aaaa a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
aaaa
aa
a
a
a
a
a
aa
a
a
a
a
a
aaa
a
a
a
aaa
a
a
a
aa
a
a
aaa
a
aaa
aaa
aaa
aa
aa
aa
aaaaaaaaaaaa aa
a a a aa a a a a a aaa a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a aa a aaaa aaaaaaaa
aa
a
a
aaa
a
a
aaa
a
a
aaa
a
a
aaa
a
aaa
a
aa
a
aaa
aaa
aaa
aa
aa
aaaaaa
aaaaaaaaaaaaaa a a aaa
a a a a aa a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a a a aa
aaa
aa
aa
aaa
aa
a
aaa
a
aaa
a
aaa
a
aaa
a
aa
a
aaa
aaa
aaa
aaa
aa
aaaaaaaaaaaaaa
aaaaaaaaaa aa a a aa a a a a aa
a a a a a a aa a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a aa
aa
a
aa
aaa
aa
aaa
aa
aaa
a
aa
a
aaa
aaa
a
aa
a
aa
a
aa
aaa
aaa
aa
aaaaaaaaaaaaaaaa
aaaaaaaaaaaaa a aa
a a a aaa a a a aaa a a a a a a a a aa a a a a a a a a a a a a a a a a a aaa a a a a a a a a a a a a a a a a a a aaa a a a a a a a
a
a
aa
a
aaa
aa
aaa
aaa
aa
aa
a
aa
a
aa
a
aa
a
aa
aaa
aaa
aa
aaaaa
aa
aaaaaaaaaa
aaaaaaaaaa
aaaaaaaa aa
a a aaaa a a aa a
a a a a a aaa a a a a a a a a a a a aa a a a a a a a a a a a a a a a a a a a aa a a a a a a a a a a a a aa a a aaa
a
a
aa
a
aaa
aaa
aaaaaa
aaaa
aaa
aa
aaa
aaaaa
aa
aaa
aa
aa
aaaaaaaaaaaa
aaaaaaa
aaaaaaa aaaaaa a aaa
a a a aa a a a a aaa a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a aa a
aaa
a
aaa
a
aaa
a
aa
a
aa
aaaa
aaaa
aa
aaaaa
aa
aaaaaaa
aa
aa
aa
aa
aa
aa
aaaaaaaaaaaaaaaaaaaaaaa aaa
a a aaaa a a aaa
a a a a a aaa a a a a a a a a a a aaa a a a a a a a a a a a a a a a aaa a a a a a a a a a a aaa a a a a aa
a
aa
a
a
aaa
a
aaa
a
aaa
aaa
aaaa
aaaaaaaaaa
aa
aa
aa
aaaaaaaa
aa
aaaaaaa
aaaaa
aaaaaaaaaaaaaaaa a a aa
a a a aa a a a a a aa a a a a a a a a aa a a a a a a a a a a a a a a aa a a a a a a a a a a a a a aaa a a a a a a a a aa a aa
a
aaa
a
a
aa
a
a
aaa
a
aaa
a
aaa
aa
aa
aaa
aa
aa
aa
aa
aa
aa
aa
aaaaaaaaa
aaaaa
aaaaa
aaa
aaa
aaaaa aaa a aa a a a aa
a a a a aa a a a a a a aa a a a a a a a a a a a aa a a a a a a a a a a a a a a a aa a a a a a a a a a a aaa a a a a a aa
The proposed research is to apply the concept of streamlines to infer permeability
fields based on the tracer breakthrough curve and pressure differences between the
injector and producers. The basic idea of my approach is to adjust the streamlines to
match the reference fractional flow and pressure data, and through streamlines to modify
the underlying permeability field.
Because there is no flow across a streamline, we can represent the flow field by
1D flow streams along the streamlines. Each streamline is associated with a time of flight
which indicates the breakthrough time. In the 3DSL streamline simulator (Batycky et al),
we solve the pressure field at given saturation distribution, obtain the streamline
distribution, then map the Buckley-Leverett solution along the 1D streamlines for a short
time period, and then solve the pressure field again and repeat the process. Because the
pressure equation and saturation equation are decoupled in 3DSL, the simulation is
speeded up significantly.
Conventional reservoir simulation history matching is time consuming because of
the large number of grid blocks. However, if we know the time of flight of the
streamline, then we will know the breakthrough time of an individual streamline.
Therefore, if the breakthrough curve for our computed permeability field does not match
the reference breakthrough curve, then we know along which streamline and in which
way to modify the permeability for a better match.
This approach is described below. To start with this project, I made the
following simplifications:
• Incompressible flow, because the streamline simulator (3DSL by Batycky et al) that I
am using works for incompressible fluid flow only;
• Piston-like displacement;
• Unit mobility ratio, valid for tracer flow study;
30
• Two dimensional;
• No constraint of the permeability value or its distribution.
Steps of the Streamline Approach to the Inverse Problem:
1. Given a reference permeability field, use the 3DSL streamline simulator for forward
simulation to obtain the reference water breakthrough curves at producers and
pressure drops between injector and producers.
2. Start from an initial uniform permeability field. Do the same simulation. Check the
match—both breakthrough and pressure drop. If it does not match the reference data,
modify the permeability as in the following steps;
3. Work on the streamlines: Calculate the time of flight for all streamlines using 3DSL
to output the coordinates of the streamlines. Sort the streamlines in the order of time
flight.
4. Compare the computed and the reference breakthrough and pressure drops. For the
breakthrough curve, check where in the curve the difference lies. Relate it to the
corresponding streamline, and then change the permeability value depending on the
difference of the breakthrough curves;
5. Repeat the simulation using the new permeability distribution. This completes one
iteration;
6. Repeat steps 2 to 5 until the match is good enough.
I obtained very promising results with this approach. In the reference field, there
are one injector and two producers. Between the injector and producer there exists a high
permeability channel, and between the injector and producer 2 there is a low permeability
barrier (See Fig. 1). Starting from a homogeneous permeability field, both the
breakthrough and pressure drops are far away from the reference (see Fig. 2). After three
iterations, I obtained a very good match both in pressure drops and breakthrough curves
(Fig. 2), which indicates that this approach converges very fast, much faster than most of
other approaches to this inverse problem.
31
Fig. 1 Comparison on Permeability Field
Producer 1
Producer 2
36
Reference Permeability Field
Computed Permeability Field after 3rd Modification
32
Fig. 2 Comparison on Breakthrough Curve
37
0.00
0.12
0.24
0.36
0.48
0.60
0.72
0.84
wat
er c
ut
0 80 160 240 320 400 480time, days
Producer 1
a a a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a a
a
a a
a
a a
a
a a a
a a a
a a a
a a
a a a
a a a a
a
a a a a a
a
aa a a
a
a a a a
a
a a a a a a
a a aa
a a a a
aa
a a a a aa a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a a
a
a
a
a
a a
a
a a
a
a a
aa a
a
a a a a a
a a a a a
a a a aa
a a a
a a
a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a a
a a
a a
a
a a a
a a a
a
a a a
a
a a a a
a a a a a
a
a a a a a
aa a aa
a a a a
a a a a a
a a a a a
a aa a a
a
a aa a
a
a
a
a
Referenceuniform3rd modi
0.00
0.12
0.24
0.36
0.48
0.60
0.72
wat
er c
ut
0 80 160 240 320 400 480time, days
Producer 2
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a a
a
a a
a a
a
a a
a a
a
a
a
a
a a
a a
a a
a
aa
a
a a a a
a a a a
a a
a
a
a a
a aa
a a a a
aa
a a a a aa a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a a
a
a a
a a
a a
a a
a
a
a a
a a a
a a
a
a
a a
a a a
a
a a
a a a
a a a
a a
a a a a
a aa a a
a
a a a a
a
a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a a a
a a
a
a a
a
a
a
a a
a a
aa
a
aa a
a a a a
a a a a
a
a a a
aa aa
a a
a a a
a a a
a
a
a
Referenceuniform3rd modi
33
Fig. 3 plots the error versus the number of iterations. The error is defined as
[ ]E E Efw i p ii
n prod
= +=∑ , ,
_
∆1
(1)
where Efw is the average absolute error in the fractional flow at different times, and E p i∆ ,
is the relative error of the pressure drops between the injector and producers at producer i.
They are defined below
En
f ffw i w i jC
w i jR
j
n
, , , , ,= −=
∑1
1
(2)
where fw i jC, , and fw i j
R, , are the computed and reference water fractional flow during time
step j at producer i, respectively.
Ep p
pp iiC
iR
iR∆
∆ ∆∆, = −
(3)
where ∆piC and ∆pi
R are calculated and reference pressure drop between the injector and
producer i, respectively.
I normalize the error in pressure by the reference pressure so that it will be within
the range of 0 to 1 and it is of the same scale as the error in fractional flow. Then I can
sum up them up to have a unified error estimation.
The solid line in Fig. 3 (a) is the sum of error at the two producers. The dashed
and dotted line are for each producer, respectively.
Comparing the computed permeability field with the reference field in Fig. 1, we
find that, with this approach, the high permeability channel is retrieved quite accurately.
For the barrier, the resolution is not very good. However, we have good matches for the
breakthrough curve and pressure drop.
34
(b)
Fig. 3 Error vs Iterations
38
0.0
0.2
0.4
0.6
0.8
1.0
Err
or
0 1 2 3(a)
a
a
a
a
b
b
b
b
a
a
a
a
a
b
a
TotalProducer 1Producer 2
0.0
0.2
0.4
0.6
Err
or
0 1 2 3Iteration
a
a
a
a
b
b
b
b
a
a a
a
b
b
b
b
a
b
a
b
E∆p at Producer 1Efw at Producer 1E∆p at Producer 2Efw at Producer 2
35
2.2 IMPORTANCE OF THE RESEARCH
History matching plays an important role in reservoir engineering. It is important
for prediction and data interpretation. In many cases, we have water or tracer
breakthrough and pressure information at the producers. This information contains much
information about the permeability distribution of a reservoir, but it is difficult to infer
this distribution. There are many approaches to this inverse problem. Most approaches
manipulate parameters at the grid-block level that corresponds to conventional simulation
grids. Because there are many cells, the optimization problem is large. By conducting the
optimization at the streamline level, the opportunity for speed improvement is great.
Since we know how each streamline affects water cut, we can speed up the inverse
process tremendously. A more typical approach would be to perturb parameters in a
more random fashion to gauge the effect of the parameter.
2.3 FUTURE WORK PLAN AND EXPECTED RESULTS
There are many simplifications in my current study. Simplification means
limitations in the application. Therefore, my future work will be focused on relaxing the
simplifications to broaden its application. My plan is to
• Release the piston-like displacement and unit mobility ratio assumptions. It is not
difficult to do since I can simply map the Buckley-Leverett solution instead of the
sharp front, and I can map the numerical solution for one-dimensional displacement
instead of the analytical one along the streamline.
• Seek a streamline simulator for compressible flow. Study my current method for
modifying a permeability field to see whether it is still valid for compressible flow.
Also study what modification of the current approach should be made for
compressible flow. Then I can make this approach work for primary recovery and
well-test problems. This will be the most difficult portion and therefore the key part
of this project.
36
• Put constraints on the permeability distribution from other information such as
seismic data, and broaden its use to three-dimensional problems. Improve the
method.
• For comparison, develop examples that use a conventional history-matching approach
to infer heterogeneity.
I will continue to work on this topic in my Ph.D. When this project is finished, I
expect that this approach will work for very general history matching purposes.
37
NOMENCLATURE
A area, L2
AS area swept, L2
AT total area of the pattern, L2
a distance between like wells (injection or production) in a row, L
d distance between adjacent rows of injection and production wells, L
EA areal sweep efficiency
fw fractional flow of water
h bed thickness, L
k permeability, L2
kro relative permeability of oil
krw relative permeability of water
l length, L
Li length of stream tube i, L
lfi distance of the displacing front from the injector in stream tube i, L
M mobility ratio
p pressure, M/L • T2
q flow rate, L3/T
Ri flow resistance of stream tube i, M/L4 • T
S saturation
Sw water saturation
tD dimensionless time
VI volume of displacing phase injected, L3
w width of a stream tube, L
φ porosity
µ viscosity, M/L• T
38
REFERENCES
1. Batycky, R. P., Blunt, M. J., and Thiele, M. R.: “A 3D Streamline-Based ReservoirSimulator” SPE Reservoir Engineering, 12, 246, (1997).
2. Craig, F. F. Jr.: “The Reservoir Engineering Aspect of Water Flooding,” Society ofPetroleum Engineers Monograph, Dallas, TX, 1971.Dyes, A. B., Caudle, B. H., andErickson, R. A., “Oil Production after Breakthrough—as Influenced by MobilityRatio”, Petroleum Transactions, AIME, 201, 27 (1954).
3. Dyes, A.B., Caudle, B.H., and Erickson, R.A.: “Oil Production AfterBreakthrough—as Influenced by Mobility Ratio,” Petroleum Transactions, AIME,201, 27 (1954).
4. Lake, L. W.: Enhanced Oil Recovery. Prentice Hall Inc., New Jersey, 1989.
5. Morel-Seytoux, Hubert J.: “Unit Mobility Ratio Displacement Calculations forPattern Floods in Homogeneous Medium,” SPE J, 6, 217, (1966).
6. Peaceman, D. W., Fundamentals of Numerical Reservoir Simulation. ElsevierScientific Publishing Co., New York, 1977.
7. Thiele, M. R., Batycky, R. P., Blunt, M. J. and Orr Jr, F. M. Jr.: “Simulating Flow inHeterogeneous Systems Using Streamtubes and Streamlines,” SPE. Reser. Eng, 11, 5,(1996).